The air conditioner includes an indoor device installed indoors and an outdoor device installed outdoors. The indoor device and the outdoor device are respectively attached with a relay terminal block, to which a power supply line or a crossover line for supplying power is connected. A terminal block that can be connected to the power supply line or the crossover line as disclosed in Patent Literature 1 is used as the relay terminal block.
The relay terminal block is fixed to a fixing part provided in the indoor device and the outdoor device by screws, respectively. In the main body of the relay terminal block, a recessed portion in which a head of the screw enters and a through-hole formed from the bottom surface side of the recessed portion, through which a shaft of the screw pierces, are formed. By piercing the screw into the through-hole and fastening the shaft of the screw to the fixing part, the head of the screw abuts on the bottom surface of the recessed portion, thereby fixing the relay terminal block to the fixing part. That is, by tightening the screw until the head of the screw abuts on the bottom surface of the recessed portion, the tip of the screw is screwed into the fixing part with a sufficient length, and the relay terminal block is thereby fixed reliably.